Wire terminal connector



Feb. 25, 1941. I. F. MATTHYSSE WIRE TERMINAL CONNECTOR- Fild Aug. 12, 1959 mu aw Hll I AN Ud drab/ fladlzyJg Kim/M ATTORNEY.

Patented Feb. 25, 1941 UNITED STATES PATENT OFFICE WIRE TERMINAL CONNECTOR Irving Frederick Matthysse, New York, N. Y., as-

signor to Burndy Engineering Company, Inc., a corporation of New York My invention relates to wire terminal connectors for use with enclosed electrical equipment such as house alrcircuit breakers, etc. These terminal connectors have usually been solder type connectors because they must fit in small space and accommodate a large range ofv conductor sizes. One object of my invention is, therefore, to provide a connector of maximum compactness.

Another object of my invention is to provide a connector which will accommodate an unusually large range of conductor sizes.

Still another object of my invention is to use the mounting screw of the" connector as the clamping screw thereby eliminating one or more screws and gaining in compactness and economy.

Still another object of my invention is to provide a connector which can readily be installed on the conductors and which does not require close fit of parts for efficient application.

A further object of my invention is to provide a connector which is sufficiently low in cost to compete with solder types.

Another object of my invention is to provide a connector high in strength, which will not distort or bend when pressure is applied by the screw.

All these objects and others are accomplished by my invention which will be disclosed below.

In small air circuit breakers for residential or commercial use, the internal mechanism and all live parts including the terminal connectors must be enclosed by the cabinet in order to prevent accidental contact with exposed current carrying parts. This is usually done by using a molded cabinet made of some phenol-formaldehyde plastic or equivalent insulating material. Generally the space available in such cabinets for the wire terminals is small because these cabinets were designed for use with solder type terminals. inasmuch as the charges for making new molds are extremely expensive, manufacturers are unwilling to provide new molds for cabinets which would accommodate larger wire terminal connectors. It was therefore necessary to design a solderless wire terminal connector which would fit into the space available in cabinets already molded.

In order to cut down a multiplicity of sizesand consequently of tools for molding cabinets and stamping metal parts-small air circuit breakers are made in a limited number of sizes. Thus the smallest size is rated at 100 amperes and may be used for all ampere'ratlngs up to that value. This means that conductor sizes ranging from #14 solid wire to 1/0 stranded cable may be used with this breaker. Inasmuch as the air circuit breaker manufacturer does not have exact knowledge as to the particular size of conductor his customer may use with the breaker it is necessary for him to supply the breaker equipped with wire terminal connectors which will accommodate the full range of wire sizes. To do this with a solderless wire connector in. the limited space available for a solder type connector is diflicult inasmuch as it is well known that usually a connector which accommodates a range of wire sizes is even larger than one which accommodates only the maximum wire size of that range.

The usual solder type wire terminal consists of a single block of metal with a hole drilled therein to receive the conductor and another to receive the mounting screw. In order to compete in cost with this. cheap construction it is necessary to design a solderless-type connector which will be equally as simple. This I have accomplished, although my connector ls made in two parts insteadof one. By using the mounting screw as the clamping screw I avoid the expense of an extra part and am able to make my device cheaply enough to be competitive in price with the solder type.

In order to obtain a good electrical connection it is necessary that the wire terminal connector exert high pressure on the conductor. This I obtain by a combination or screw pressure and thrust against the tapered back or the outer shell. Naturally this thrust puts considerable strain on the outer shell and this must be so designed as to withstand the thrust without distorting or bending. To accomplish this I provide side walls which reinforce the outer shell and prevent the front lip or back from bending outwardly when pressure is applied. Any such motion may prove to be extremely detrimental because the motion may be suillcient to apply pressure to the molded barriers and subsequently cause the barriers to crack or break. This would cut down the insulating efficiency of the breaker and may even cause it to become useless.

l accomplish these and other objects and obtain my new results as will be apparent from the device described in the following specification, particularly pointed out. in the attached claims, and illustrated in the accompanying drawing, in which:

Fig. 1 is a top view of the air circuit breaker terminal portion, showing two wire terminal connectors in place.

Fig. 2 is a side view of the same, partially sectioned to show the internal structure of one of the terminal connectors.

Fig. 3 is a. sectional view of one of the wire terminal connectors and terminal portion showing an installation on a small diameter wire.

Fig. 4 is a sectional view illustrating a rearrangement of the parts useful for gripping small wires.

Reference numeral I0 designates the air circuit breaker terminal portion having recesses Ii, for receiving thewire terminals l2. A wall l3 separates the recess II from the base recess l4 running the length of the entire portion,and an aperture I5 joins the two recesses. An internally threaded sleeve I6 is riveted within the aperture to anchor the pressure screw l'l passing through aperture I8 in connector body 20 and pressure bar 19 pressing against conductor 30 within the connector body.

The connector body 20 comprises a shell like section within which is formed a tapered wall 2| forming the back-section, a concave conductor supporting front wall 22 and two reinforcing side walls 23 and 24. A seat 25 is preferably formed on the bottom of the connector body, within which a plate 26 conducting the current to the circuit breaker may be accommodated. The plate is supported directly on the riveted sleevej IS. The pressure bar I 9 contains an oval aperture 21 for the pressure screw I1, a tapered back section 28 corresponding to the tapered wall 2| of the connector body, and a concave front section 29 into which the conductor 30 may be seated. The conductor itself is inserted through apertures 3| and 32 in the side walls 23 and 24 of the connector body. A washer 33 is positioned between the head of the screw l1 and the pressure bar.

In operation, the conductor 30 is inserted into aperture 3| of the connector body l8 through the recess l I in the air circuit breaker terminal portion ID. The aperture 3| conforms to the concave shaped front wall 22 so that pressure bar l9 will compress the conductor uniformly against wall 22 by applying pressure through concave section 29. v

The combination of screw pressure and thrust against the tapered back 2| results in a high pressure being applied to the conductor 30 insuring a good electrical connector. Simultaneously the connector body I8 is being securely and rigidly mounted to the riveted sleeve.

In the event it is desired to clamp a conductor 34 of minimum cross-section, the pressure screw is loosened until the pressure bar I8 can be rotated 180, as shown in Fig. 3.

The tapered end section 28 of the pressure bar can be used to compress the conductor 34 to the concave front wall 22, the oval aperture 21 permitting the pressure bar l9 to be seated lower in the connector body 38 and closer to the concave front wall 22.

If the conductor is'of extremely small diameter, the pressure bar 19 may be reversed with respect to the pressure screw, and convex section 35, formed opposite the concave section '29, may be used to compress the conductor 31 against the front wall 22, as shown in Fig. 4, the convex and concave surfaces conforming to one another enabling a conductor of minimum size to be grasped therebetween.

The resulting connector is inexpensive to manufacture and contains a minimum. of parts for the wide range of conductors capable of being satisfactorily supported therein. By providing the adjustable pressure bar with a tapered I: .01: section for engagement with the wall, the clamping screw can apply satisfactory pressure within the wide range of conductors accommodated. The shell body is adapted towithstand large pressures thus produced, and the simultaneous clamping of the conductor and locking of the connector into position makes for ease and economy in installation.

I have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and'described are only some of the many that can be employed to attain these objects and accomplish these results.

What I claim and desire to secure by Letter Patent, is as follows:

1. A connector for attachment to a terminal block, comprising a pressure screw for threaded attachment to the block, a connector body having side walls and a bottom with an aperture therein for entrance of the pressure screw and an aperture in a side wall thereof for the lateral entrance of a conductor; a pressure bar, having a central aperture for entrance of the pressure screw and a conductor engaging surface, the inside of said the terminal block, thescrew will simultaneously clamp the pressure bar and the connector body about the conductor and support the connector and conductor to theterminal block.

2. A connector for. attachment to a terminal block, comprising a pressure screw for threaded attachment to the block, a connector body having side walls and a. bottom with an aperture therein for entrance of the pressure screw and an aperture in a side wall thereof for the lateral entrance of a conductor; a pressure bar, having a central aperture for entrance of the pressure screw and a plurality of conductor engaging surfaces for alternatively engaging the conductor depending on the size thereof, the inside of said connector body having a conductor engaging surface and a pressure bar engaging surface, the conductor engaging surface of said connector body and each of the conductor engaging surfaces of said pressure bar adapted to cooperate. for pressing the conductor in a direction, oblique to the axis ofsaid pressure screw,'whereby when said pressure block, comprising a; pressure screw for threaded attachment to the block, a connector body formed into a shell with side walls, front and back sections and a bottom with an aperture therein for entrance of the pressure screw and an aperture in a side wall thereof for the lateral entrance of a conductor; a pressure bar, having a, central aperture for entrance of the pressure screw and a conductor engaging surface, the inside of said connector body having a conductor engaging surface and a pressure bar engaging surface rigidly connected to each other by said side-walls and said bottom, the conductor engaging surfaces of said connector body and of said pressure bar shaped and positioned for pressing the conductor in a direction oblique to the axis of said presure screw, whereby when said pressure screw and conduci'or are inserted into their respective apertures, and the pressure screw threadedly engages the terminal block, the screw will simultai'ieouslyv clamp the pressure bar and the front wall of the connector body about the conductor and support the connector and conductor to the terminal block.

4. A connector for attachment to a terminal block, comprising a pressure screw for threaded attachment to the block, a connector body formed into a shell with side walls, front and a tapered back section with an aperture therein for entrance of the pressure screw and an aperture in a side wall thereof, for the'lateral entrance of a conductor; a pressure bar, having a central aperture for entrance of the pressure screw, a tapered end for engagement with the corresponding tapered back section of the shell body, and a conductor engaging surface, the inside of said connector body having a conductor engagin surface rigidly connected to the tapered back section by said side walls, the conductor engaging surfaces of said connector body and of said pressure bar shaped and positioned for pressing the conductor in a direction oblique to the axis of said pressure screw, whereby when said pressure screw and conductor are inserted into their respective apertures, and the presure screw threadedly engages the terminal block, the screw will simultaneously clamp the pressure bar and the connector body about the conductor and support the connector and conductor to the terminal block.

IRVING FREDERICK MA'I'I'HYSSE. 

